Electric controller.



A. 0. EASTWOGD. ELECTRIC CONTROL LEE APPLIUATION FILED $358124, 1910.RENE WED JULY 16,1912.

- Patented Oct. 8, 1912 2 SHEETS-SHEETI.

FIG. 1

WITNESSES iNVENTOR ,9

I AM/24M g7 m EAS- 790B" ELECTRIC CO1? APPLIQATIQE FILED 322m 1910.1,040,292'

TEOLLER.

RENEWED JULY 15, 1912v UNITED STATES: PATENT OFFICE.

(I. EASTNOOD, OF CLEVELAND, OHIO, ASSIG-NOR TO THE ELECTRIC CGN- TEOLLERAND MANUFACTURING COMPANY, OF CLEVELAND, @515), A CQR?OIEIA TIDN 9F@HIO.

ELECTRIC CONTROLLER.

specification of Letters Patent.

Patented Oct. 8,191.

Application filed September 24, 1910, Serial. No. 588,577. Renewed July15, 1912. Serial No. 709,575.

To all whom it may concern."

Cleveland. in the county of Cuyahoga and State of Ohio, have inventednew and usetul improvements in Electric Controllers, of?

which the following is a specification.

My invention relates to electric controllers of that type in which aseries of individually I operated switches are employed in control-;ling the [low of current in an electric circuit or circuits. Incontrollers of this t pe, to carry out a given scheme of control, it isnecessary, or at least advisable, to provide means for compelling thevarious switches to close in an invariable sequence to carry out thescheme of control for which the controller is specifically designed.

My invention relates particularly to means for compelling suchinvariable sequence in the closure of a series of independently operatedswitches.

My invention. in addition to making the closure of one switch dependupon the closure of a switch which precedes it in normal operation, goesfurther than this and provides means whereby the succeeding switchcannot close not only till the preceding switch has closed, but till thecircuit controlled by the preceding switch has closed. This I consider apoint of material improvement over controllers in which the closure ofone switch is made to depend upon the closure of the preceding switch,but such closure does not depend on whether or not the circuit throughthe preceding switch is closed.

My invention has the further advantage that so called auxiliary orcontrol circuit contacts are removed from the switches which control themain. circuit connections. Referring to the accompanying drawings,

Figure 1 is a diagrammatic view illustrating my invention. in connectionwith a simple non-reversing controller for a series-Wound motor. Fig. 2is a sectional View partly in elevation of a form of relay which isadapted for use in my invention.

On Fig. 1, S is a main switch connecting the motor and the controller toa source of current supply. A is the armature of the motor; F, theseries field winding; R, R and R, sections of resistance adapted to hesuccessivelyconnected in the controlled circuit. These sections ofresistance are governed respectively by the magnetically-oper- Be itknown that l, Anita-inn C. l l-is'rwoon, j a citizen of the UnitedStates, residing at ated switches S, S", and S. Vvhen switch S isclosed, the resistance section B is in series with the motor. Whenswitch S closes, the resistance section R is placed in parallel with theresistance R, thus reducing the resistance in the motor circuit. \Vhenswitch S closes the resistance section B is connected in parallel withresistance sections R and R thus further reducing the resistance, andwhen the switch 3* closes, the entire resistance is short circuitedthrough the wire 4. The switches S to 5* are provided with actuatingwindings C to C, respectively. M indicates a master switch of the drumtype, by which the windings ot' the switches may be successivelyenergized at the will of the operator by turning the drum of the switchso asto bring the contact strips n to 9 successively into contact withthe stationary contact fingers m to m, respectively. The lower ends ofeach of the actuating windings of the magnetic switches are connected,respectivel), to the contact fingers m to'm of the master switch. Eachof the switches S to S is provided with a series relay, the winding ofwhich is included in the circuitclosed by the switch. Each of theserelays controls a pair of normally open contacts such that when currentflows through the winding of the relay, these contacts are bridged andelectrically connected together. It will be seen that the contacts ofthe relay L are included in the circuit of the winding of the switch S";the contacts of the. relay L are included in the circuit or thcwiirlingof the switch S and the contacts of the rclay L included in thecircuit()f the winding of the switch S.

The operation of this controller may be described as follows: Assumingtha the main switch S is closed and that the (m ni of the masterswitchor controller is moved to bring the contacts or and '21. into contactwith the respective fingers 1a and m, the; following circuit will beestablished: from the positive side of the switch S through. the wire 1,the finger m of the master switch, the contact strips 1i and n, thecontact linm the winding C of the switch S, and... the wires 5 and 3 tothe negative side. of the switch 5. This completes the circuitthroughthe winding of the switch S which will then,close. The circuit throughthe v sistance in the motor circuit.

controlled by the switch S includes the motor is then completed asfollows: from the positive side of the switch S through the wire 1, thecontacts bf the switch S', the winding of the relay L, the resistancesection ll, the wire 2, the field F and the arma' ture A of the motor,and the wire 3 to the negative side of the switch S. Current thus flowsthrough the winding of the relay L which lifts its plunger and bridgesthe contacts 'a.

W hen the master switch is moved into its next position, that is, whenthe strip a is brought into contact with the finger m the winding C ofthe switch S is energized through the following path: from the positiveside of the switch. S, through the wire 1, the contact finger m, thecontacts n, 9%., and a of the master switch, the finger m the winding Cof the switch S the contacts a of the relay L, and the wires 5 and 3 tothenegative side of the switch S. The switch S then closes, thusconnecting the resistance section R in parall" with the resistancesection B", reducing the totalre- The circuit winding of the relay if,and if this circuit is complete, that is to say, if there are no brokenconnections in the circuit controlled by the switch S the winding of therelay L will be energized, and this relay will lift its plunger, thusclosing the contacts a which are in the circuit of the winding C of theswitch S which is the next switch to close. Similarly, by furtherrotation of the drum of the master switch, the switch S is caused toclose, thereby energizing the relay L and putting the switch S in aposition to be closed, ,upon moving the master switch another step. Whenthe switch 5 closes, all of the resistance is short circuited, currentthen flowing through the motor as follows:

from the positive side of the switch S,

throughthe wire 1, the winding of the relay U, the contacts of theswitch 5*, the wire 4, the field and the armature of the motor, and thewire 3 to themegative side of the switch S. The closure of the switchS", therefore, in addition to short circuiting resistance sections R, Rand R also short circuits the windings of the relays L and L These tworelays, therefore, drop their plungers and the switches S and Sautomatically open. The switch 8*, however, is maintained closed throughthe contacts of the relay L since the motor current flows through thewinding of this relay.

"When it is desired to stop the motor, the drum of the master switch isturned back to its initial or ofi-position, which causes the switch S5to open and interrupt the motor circuit.

adapted to switches, or they may be shunted so that any desired portionof the motor current will flow through the relay windings. I have.indicated at K a shunt-around the winding of the relay L By properlyproportioning the resistance of this shunt with respect to theresistance of the winding .of the relay L any desired proportion ofmotor current may be causedto flow through the relay form, theadditional valuable result may be obtained of preventing successiveclosure of the switches until the current taken by the motor has droppedto a suitable value; in other words,succeeding switches will not closeunless the motor'current is below a predetermined value. By this meansthe current taken by the motor during acceleration may be madesubstantially constant and independent of the rapidity with whichtheoperator moves. his master controller. Where it is desirable to do so,the master controller, having a con-tact for each switch, -may bereplaced with a simple switch controlling the circuit of the switch S,the other switches closing automatically in predetermined order and onlyclosing when the current taken by the motor is at a predetermined andproper value.

In Fig. 2 l have shown a form of relay the purposes of the relays L to LIn this relay 6 is a frame of magnetic material, the upper portion ofwhich is provided with a central depending pole piece 12 K is thewinding of the relay adapted to-beconnected as indicated in Fig.1. 6 isa core of magnetic material provided with a stem or extension 6 also ofmagnetic material. This stem 6 extends into the bore of a hollowadjustable plug 6 of mag netic material. The upper end of the core I)'is provided with an extension Z1 of brass or other non-magneticmaterial. This extension'carries at its upper end a contact disk 6suitably insulated from the stem. and adapted to bridge or connect thestationary. contact points 6 and 6. The shoulder 6 serves to limit thedownward motion of the core. This relay possesses the remarkablecharacteristic that, if a current at or below a predetermined valueflows through the .winding K, the core 6 will be attracted to the boss 5thereby causing the relay to face the plug; Z) and the core will notuntil the current has been reduced to the said prede ermined value. Thevalue of current at which the relay will act to bridge its contacts maybe adjusted in various ways, but preferably by the air gap bet "eon theface the plug and the lower face of the core 6*, this being accomplishedby screwing the plug 1 in or out.

Y the switch shown in Fig. 2, the mag netic flux appears to tow in adivided path in a part oi the magnetic circuit, when the windingenergized. The magnetic flux may be regarded flowing from a point in theframe T), such as the pole across the air ap inin'iediately below thepole and into the core Zr. At the lower end of the core the fill}:divides into two paths, one path through the core-extension 5 and intothe plus J and the lower end 01 the me and the other path being from thelower end of the core b across the air-gap immediately below it and intothe top of the plug 72 and thence through the plug to the lower end ofthe frame Z). The flux i the upper gap produces a "ce tending to raisethe core 71*, While the i'i lK. through the lower gap produces a forcetending to prevent the core from being raised. H the winding is exciteda relati vely low value, the larger part of the flux; produced therebywill flow through. the extension 6 and since this flux passeshorizontally into the frame, there is no tendency to prevent the plungerfrom moving upwa dly, only a small part of the flux passing across thelower gap around the extension 5 the winding is excited at a high valuethe restricted area in the magnetic circuit through the extension forcesmore llux to pass across the lower gap into the plug or pole 5, therebyincreasing the force tending to prevent the upward movement of the core.The extension Z) is in the said applications oi Cantield surrounded by asleeve of non-magnetic material which serves as a guide tor the core andprevents the core vfromsticking to the pl ugb l disclaim the specificconstruction of this r lay as part of this invention as the same is theinvention of Harry R. Canfield and tor-ins the subject matter of his[applications tor il'nited States Patent, Number SHEWO tiledtrleptcinber 21, 1910', and Se I :51, tiled January i5) rial Number 30H, n, do. how-o'er, claim @combinatiou including; this reuiy or itsequivalent connected 'l minted in Fig. l, or in modified ways rezuilysuggest themselves to iii skilled in the a 1 rice now to Fig. 1, withthe relays L to L constructed as shown in Fig. 2, as some that theoperator moves his master switch suddenly to the full speed position,that is, until all of the contact strips n to a are in contact withtheir respective fingers m to m". A circuit is then completed throughthe winding G of the switch S, causing this switch to close. 1n closingthe switch S closes the main motor circuit through the winding of thefirst relay L. It the current which then flows is greater than that forwhich the relay is adjusted, the relay cannot lift its plunger and thewinding C of the switch remains deenergized. When, however, the motorcurrent has fallen to a safe or predetermined value, the relay lifts itsplunger, thus brid i ing the contacts a and completing the circuitthrough the winding C of the switch main or motor circuit through thewinding of the relay which in a similar manner cannot permit the closureof the switch S until the current has dropped to a prede termined value,11 the current exceeds the value 7 which the relay L is set. The relay Lacts in a similar manner to prevent the closure of the switch S untilthe current has dropped to a predetermined value.

With the described scheme of control, the operator may control thenumber of switches closed by the position to which he moves the masterswitch, but he cannot, however, control the rate of progression of theclosure of the switches since the rate is governed by the motor currentthrough the agency of the relays L to L; nor can he cause the switchesto close out of their predetermined order, which is also determined bythe relays Li to L. lit will be understood that, if open circuits existin any or the resistance sections R, R and R or their connections, thesuccessive closure of the switches will be interrupted when this pointis reached in the acceleration and the motor cannot be brought up tofull speed until the trouble is repaired. For instance, if there shouldbe an open connection in the circuit of the resistance section R whenthe switch closes, no current could flow through the winding of therelay L consequently, the winding of the switch S cannot be energireduntil the trouble is remedied. Similarly, if there is an open circuitin-the connection including the resistance section R no current couldflow through the winding of the relay L even though the switch S isclosed; consequently, the switch S could not be closed.

clain ln electric controller, the combination of a series ofmagnetically operated switches to be successively closed, the circuitsof the actuating windings of the said magnetically operated switchesbeing in The switch S then closes, closingthe' iiu shunt with or derivedfrom the controlled circuit, and means for preventing further successiveclosure of said switches in case any one of said switches when closedfails to establish a circuit through its main contacts.

In combination, a series of magnetic switches each adapted to close apair of main contacts, each of said switches having an actuating windingindependent of the circuit controlled by said main contacts, and meansfor preventing the closure of succeeding switch unless current flowsthrough the main contacts of the switch which precedes in operation.

3. The combination, in in electric controller, of a series of switcheseach having main contacts and an actuating winding, relays associatedwith certain of said switches and having normally open contacts in thecircuit of the winding of the switch next to close, said relays havingwindings arranged to be successively connected in the controlled circuithy the closure of the main contacts of the said switches and movablecontacts on said relays actuated by the said windings to close the saidnormally open contacts.

st, in an electric controller, a series of magnetically-dperatedswitches to be suc cessively closed, means for inforcing said successiveclosure, said means comprising normally open contacts in the circuit ofthe winding of each of said switches except the first to operate, arelay for each of said normally-open contacts, said relay being arranged to connect said contacts when its winding is energized, thewinding of the relay controlling the contacts in the circuit of thewinding of thesecond switch being in cluded in the controlled circuit bythe closure of the first switch, the winding of the relay controllingthe circuit of the winding of the third switch being included in thecontrolled circuitloy the closure of the sec- 0nd switch.

5. In an electric controller, a series of consecutively-acting magneticswitches, a relay adapted when energized to close the circuit throughthe actuating winding of each of said switches, except the first toclose, each of said relays being included in the controlled circuit bythe switch which precedes in operation.

6. In an electric controller, a series of consecutively-acting magneticswitches, a relay arranged to control the circuit through the actuatingwinding of each of said switches, except the first to close, each ofsaid relays being included in the controlled circuit by the switch whichprecedes in opration, said relays havin, normally open Contacts beingconstructs to close their contacts only when the current through theirwindings is less than a predetern'nned amount.

notc es 7. The combination, in an electric con troller, of a series ofswitches each having 8. The combination, in an electric conc troller, ofa series of switches, each having main contacts and an actuatingwinding, re lays associated with certain of said switches and havingcontacts in the circuit of the winding of the switch next to close, saidrelays having windings arranged to he successively connected in thecontrolled circuit by the closure of the main contacts of said switches,each of said relays having normally open contacts being so constructedas to close its contacts only when the current through its winding isbelow a predetermined value, and means for adjusting the said relays asto the current value at which they will close their contacts.

9. In an electric controller, a series of magnetically operated switchesto be successively closed, means for iniorcing their successive closure,said means comprising normally open contacts in the circuit of thewinding of each of said switches except the first to operate, a relayfor each of said normally open contacts, said relay being ranged toconnect said contacts when ts winding is energized by a current below apredetermined value, the winding of the relay controlling the contactsin the circuit cf the winding of the second switch heing in cluded inthe controlled circuit by the clo sure of the first switch, the windingof the relay controlling the circuit of the winding of the third switchbeing included in the controlled circuit by the closure of the sec ondswitch, and so on.

10. In an electric controller, a series of magnetically operatedswitches to he succea sively closed, means for intorcing theirsuccessive closure, said means comprising normally open contacts in thecircuit of the winding of each of said switches except the first tooperate, a relay for each of said normally open contacts, said relaybeing ar-- ranged to connect said cont-acts when its winding isenergized by a current below a predetermined value, the winding of therelay controlling the contacts in the circuit of the winding of thesecond switch being included in the controlled circuit by the ole sureof the first switch, the winding of the rela controllin the circuit ofthe'windin ,1 operation, each of said relays being so constructed as toclose its contacts only when an LAG u rent through its winding is belowa ermined value.

in an electric controller, a series of consecutively acting magneticswitches, a rec third switch being included in the lay adapted whenenergized to close the circuit through the actuating winding of each ofsaid switches except the first to close, each of said relays beingincluded in the controlled circuit by the switch which precedes inoperation, each of said relays being so constructed as to close itscontacts only when the current through its winding is below apredetermined value, and means for adjusting said. relays as to thecurrent value at which they will close their contacts.

Signed at Cleveland, Ohio, this 19th day 30 of September, 1910.

ARTHUR C. EASTWOOD.

Witnesses:

J. H. HALL, H. M. DIEMER

